From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80835][MODERATE 7.0] crypto: qcom-rng - Remove crypto_rng interface Date: Fri, 04 Sep 2026 17:02:49 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80835 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: bb474dcd9d0224264a27a60891f00872b879835f List-Id: CVE: CVE-2026-80835 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: crypto: qcom-rng - Remove crypto_rng interface Commit: bb474dcd9d0224264a27a60891f00872b879835f Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bb474dcd9d0224264a27a60891f00872b879835f Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80835 Analysis date: Fri, 04 Sep 2026 17:02:49 -0400 ActionableScore: 5 ActionableScore lower bound: 3 Actionable bucket: Actionable Moderate at minimum Manual review required: YES Summary: The qcom-rng driver exposed the same hardware RNG through both crypto_rng and hwrng without shared synchronization, allowing concurrent register access that may produce repeated or non-random output and weaken cryptographic material on affected Qualcomm platforms. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80835 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80835 The original announcement does not normally provide a security severity estimate, CVSS assessment, or enough information to determine whether the reported kernel bug represents a practically relevant security issue. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. It combines an autonomous classifier with LLM-assisted technical analysis and a separate ActionableScore mechanism. The purpose of this report is to prioritize Linux kernel CVEs before manual review, identify cases that require prompt investigation, and support automatic closure of issues that are unlikely to have meaningful security impact. Published priority for this report: MODERATE 7.0 Manual review required: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-80835 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80835 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N';CWE-362;CWE-330;CWE-338;CWE-667;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N';BEST CVSS score: '6.3';DESCR 'The qcom rng driver exposed the same hardware RNG through both crypto_rng and hwrng interfaces without common synchronization for accesses to the shared hardware registers. Concurrent generation through qcom_rng_generate() and qcom_hwrng_read() can cause repeated output or non random values, which may weaken cryptographic material that depends on this RNG. For the CVSS the PR:L is used because a local user or local process is needed to trigger the crypto_rng side through AF_ALG while hwrng activity is present. The issue is not directly network reachable. Impact is not a kernel crash but possible confidentiality and integrity degradation through weakened randomness. The base score uses low C and I impact, while the paranoid score treats RNG output degradation as potentially high impact in deployments where the affected RNG contributes to keys, nonces, or tokens.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) YES LOCK INIT ERRORPATH HARDWARE LINUS INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 5 * Final recommended bucket: **Actionable Moderate at minimum** ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. The removed crypto_rng interface was reachable through AF_ALG rng operations when enabled. * Local unprivileged high-control kernel data-plane API refinement: +1. AF_ALG lets a local process issue controlled RNG generation requests and shape timing against hwrng activity. * Confidentiality impact plausible: +1. Repeated or non-random RNG output can weaken keys, nonces, session material, or tokens generated from affected entropy paths. * Integrity impact plausible: +1. Weak randomness can undermine cryptographic integrity assumptions for signatures, authentication tokens, or protocol nonces. * Hard or unreliable race / special timing required: -1. The issue depends on concurrent access through crypto_rng and hwrng to the same hardware registers. * Legacy / non-default execution mode: -1. The commit explicitly states that the crypto_rng AF_ALG rng algorithm type is not used in practice. Paranoid additional interpretation: * Broad/default/common subsystem or broadly deployed exposure: +1. On affected Qualcomm platforms, hwrng can be part of the system entropy source, so RNG quality problems may affect security-sensitive consumers. * Practical exploit chain strongly implied: +1. The commit directly states potential repetition of output and output of non-random values, which is a concrete cryptographic failure mode rather than only a theoretical race. * Paranoid score does not subtract the AF_ALG rarity as strongly, because an attacker can intentionally use the exposed crypto_rng interface if it is registered. No memory-corruption signals are awarded. This is not UAF, OOB write, double free, type confusion, or arbitrary write. ## 3. Reachability analysis The realistic trigger is local. A local process would need to use the crypto_rng side, likely through AF_ALG rng, while hwrng reads occur concurrently. No direct network reachability is supported by the patch. Namespaces do not obviously create a separate remote or container escape path, but local access to AF_ALG may make the crypto_rng side reachable without full root privileges depending on product configuration. The issue is hardware and configuration dependent because it requires the qcom-rng driver on affected Qualcomm SoCs and the removed crypto_rng registration path. Call-site confidence: medium. The patch includes the removed crypto_rng implementation, the hwrng implementation, and the shared qcom_rng_read hardware access path, but not all possible consumers of AF_ALG rng or hwrng entropy. ## 4. Severity interpretation This behaves more like an actionable cryptographic Moderate than an ordinary low-risk cleanup. The patch does not support privilege escalation or kernel memory corruption, so it should not be classified as Important solely on bug class. However, RNG output repetition or non-random output can have high downstream security impact when the affected RNG contributes to cryptographic material. Conservative handling is Borderline / manual review recommended. Paranoid handling is Actionable Moderate because cryptographic confidentiality and integrity can be affected even without crash or memory corruption. ## 5. One-sentence report phrase The qcom-rng driver exposed the same hardware RNG through both crypto_rng and hwrng without shared synchronization, allowing concurrent register access that may produce repeated or non-random output and weaken cryptographic material on affected Qualcomm platforms. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED. YES REQUIRES MANUAL CHECK because this is not memory corruption, but RNG quality bugs can silently affect confidentiality and integrity depending on how the affected platform feeds entropy into keys, nonces, and tokens. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: crypto: qcom-rng - Remove crypto_rng interface Commit: bb474dcd9d0224264a27a60891f00872b879835f Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bb474dcd9d0224264a27a60891f00872b879835f Commit description: qcom-rng.c exposes the same hardware through two completely separate interfaces, crypto_rng and hwrng. However, the implementation of this is buggy because it permits generation operations from these interfaces to run concurrently with each other, accessing the same registers. That is, qcom_rng_generate() synchronizes with itself but not with qcom_hwrng_read(). This results in potential repetition of output from the RNG, output of non-random values, etc. Fortunately, there's actually no point in hardware RNG drivers implementing the crypto_rng interface. It's not actually used by anything besides the "rng" algorithm type of AF_ALG, which in turn is not actually used in practice. Other crypto_rng hardware drivers are likewise being phased out, leaving just the hwrng support. Thus, remove it to simplify the code and avoid conflict (and confusion) with the hwrng interface which is the one that actually matters. Fixes: f29cd5b ("crypto: qcom-rng - Add hw_random interface support") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Reviewed-by: Dmitry Baryshkov Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Changed files: drivers/crypto/qcom-rng.c crypto/internal/rng.h Diff excerpt: Not included in this email. See the upstream URL for the full patch. Full patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bb474dcd9d0224264a27a60891f00872b879835f ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80835 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80835 The original CVE announcement normally does not include a security-level estimate. In particular, it may not contain a CVSS assessment, an impact level, or enough information to determine whether the reported bug is a practically relevant security issue. One purpose of this parallel CVE list is to provide that missing technical and prioritization information. The original goal of the AL-KERNEL project was to prioritize Linux kernel CVE analysis automatically before manual review. The system can also help identify non-security issues that may be suitable for automatic closure. This report was generated by AL-KERNEL, an AI-assisted Linux kernel vulnerability analysis system developed by Alexander Larkin. The first analysis stage combines an autonomous classifier with additional LLM-based analysis. The autonomous classifier runs locally on a CPU and is based on a backpropagation neural network. Together, these mechanisms produce a technical vulnerability description, identify likely weakness types, estimate CVSS severity, and provide input for ActionableScore. Two CVSS estimates are retained because incomplete kernel vulnerability information often permits more than one defensible interpretation: Conservative CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N The Best / paranoid CVSS score: 6.3 The conservative vector represents a lower-impact interpretation. The Best/paranoid vector intentionally represents a plausible upper-bound interpretation and should not automatically be treated as demonstrated real-world impact. CVSS may also need to be adjusted for a particular Linux deployment, because actual reachability, privileges, enabled kernel configuration, hardware, namespaces, exposed device nodes, and other environmental conditions can differ significantly between systems. A separate ActionableScore mechanism evaluates practical remediation urgency. Its analysis may include reachability, attack prerequisites, subsystem exposure, memory-corruption characteristics, denial-of-service reliability, and possible confidentiality, integrity, or privilege-escalation impact. Conservative ActionableScore: 3 Paranoid ActionableScore: 5 The final base severity is taken directly from the second tab-separated field of the AL-KERNEL classification result. ActionableScore does not replace or independently override that final AL-KERNEL decision, and if ActionableScore adjusted impact level of ALKERNEL, then you would see self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7. For an AL-KERNEL result of MODERATE, this report uses the following additional presentation split: ActionableScore below 5 -> MODERATE REGULAR ActionableScore 5 or more -> MODERATE 7.0 The distinction between MODERATE REGULAR and MODERATE 7.0 makes it possible to identify Moderate issues that should receive manual analysis and fixes before lower-priority MODERATE REGULAR issues. In many cases, MODERATE REGULAR fixes may wait for a later rebase or routine update. There is one override in which MODERATE REGULAR becomes MODERATE 7.0 even when the ActionableScore is below 5. When the AL-KERNEL result contains the KPANIC flag, a MODERATE result is always presented as MODERATE 7.0. The KPANIC flag selected with few regexps without usage of AI at all, so it helps to detect cases when Kernel Crash happens and similar (to filter False-Negative results from the LLM usage). KPANIC indicates that a reliable kernel crash, kernel panic, or similarly serious kernel availability impact was identified by the classification workflow. AL-KERNEL base severity for this report: MODERATE KPANIC detected for this report: NO Published priority for this report (same as in Subject): MODERATE 7.0 These results are intended to support engineering triage. They are machine-generated estimates, and cases marked for manual review should be validated by a human security engineer before final disposition. For more info read docs linked from here: https://kernelcve.org/ (and you can submit you own patch there to generate such a report for non-existant CVE-id yet). Note that in many cases this AI tool selects higher severity, than real is (means you can expect Importants instead of Moderate 7.0 or Moderates 7.0 instead of regular Moderates). If you see such cases, please use reply email interface to add additional manual analyses info to this particular CVE. And please, please, let me know when you see Lows instead of Importants or Important instead of Low (because particular for such cases I need to tune this AI tool to make it better for this one and next similar). My contact email for such notifications is alexanjelausa@gmail.com (and both send reply to CVE record itself too and see "reply" button below for howto reply).